CAIRO (AP) — Egypt's revolutionary activists, relatively muted since the country's July coup, showed a new vigor Tuesday, scuffling with supporters of the military-backed government in Cairo's Tahrir Square and wrecking a state memorial dedicated to protesters killed in the country's nearly three years of turmoil, only hours it was inaugurated.

The vandalizing of the memorial — which so far consisted only of a pedestal waiting for a planned statue — reflected the youth activists' anger against what they see as an attempt by the current military-backed rulers to paper over past bloodshed, rewrite history and co-copt the revolutionary spirit.

The interim prime minister inaugurated the memorial's base Monday afternoon with great fanfare. By Tuesday morning, it was reduced to a lump of concrete covered in revolutionary graffiti after activists before dawn ripped off its stone cladding and spray-painted it with slogans denouncing both ousted Islamist President Mohammed Morsi and his nemesis, military chief Gen. Abdel-Fattah el-Sissi.

"The revolution continues," one slogan across it proclaimed. "Down with all those who betrayed— military, former regime, or Muslim Brotherhood." Activists set a mock coffin draped with the Egyptian flag onto the pedestal.

Secular, leftist youth activists were in the forefront of Egypt's revolutions, starting with the 2011 uprising that ousted autocrat Hosni Mubarak. But they have been overshadowed since. They have been further divided over how to deal with the new order after the military removed Islamist Mohammed Morsi, the country's first freely elected president, on July 3 following massive protests against him.

Since then, the streets have been dominated by rallies in support of the military or smaller, near daily protests by Morsi's backers, amid a heavy crackdown on Islamists. Non-Islamist critics of the new leadership have been reluctant to speak out for fear of being seen as supporting the Brotherhood and Morsi, whom they also sharply oppose.

But revolutionary groups were energized by the second anniversary Tuesday of the "Mahmoud Mahmoud" clashes — one of the fiercest confrontations between protesters and security forces, named after the street off Tahrir where they took place.

The 2011 clashes were prompted by a crackdown on anti-police brutality protests that spiraled into demands for the end of rule by the military, in power after Mubarak's fall until Morsi's 2012 inauguration. More than 40 protesters were killed. Last year, three were killed when police under Morsi cracked on down protests marking the anniversary — turning the date into a rallying point for sentiment against the military, police and the Brotherhood.

On Tuesday afternoon, hundreds of activists gathered in Tahrir. They raised white flags showing pictures of slain protesters. Some chanted slogans against police, holding the current and previous governments responsible for failing to bring top security officials to justice in protester killings.

Scuffles erupted when a group of supporters of the military also entered, carrying portraits of el-Sissi — whose birthday was on Tuesday. The two sides hurled stones at each other in intermittent clashes as activists chased out the military backers. Police fired one volley of tear gas, but largely stayed clear of the square.

No Morsi supporters were seen in the square.

The government's move to erect a monument in Tahrir turned the occasion into a fight over the memory of hundreds killed in Egypt's waves of protest — against Mubarak, against the military and against the Brotherhood.

Officials said the monument honors martyrs of "the two revolutions" — the anti-Mubarak uprising and the giant wave of anti-Morsi protests by millions that began June 30 and prompted his ouster.

Infuriated revolutionary activists point out that most protesters that past 2 ½ years were killed by police. They say security forces have returned to the brutal ways they were notorious for under Mubarak — now under the pretext of fighting a war against terrorism.

Activists painted over an iconic mural of graffiti immortalizing martyrs on Mohammed Mahmoud Street. They covered it over with a camouflage pattern in shades of red, symbolizing blood security and military have spilled in crackdowns.

Many of the activists in Tahrir on Tuesday wore eye patches, commemorating protesters who were shot in the eyes and blinded during the Mohammed Mahmoud clashes.

"We don't want to be ruled by soldiers and we don't want to be ruled by a Brotherhood that peddles religion," protesters chanted around the damaged pedestal. "I want to say a word in your ear el-Sissi, don't even dream of becoming my president."

El-Sissi has not ruled out a run in next year's presidential election.

The activists' protests put supporters of the military in a difficult rhetorical corner. Military supporters have depicted the military and the new government as the inheritors of the revolution after removing Morsi and his Brotherhood.

After initially trying to blame the pedestal vandalism on the Brotherhood, commentators on pro-military media criticized the activists who did it, saying they were only helping the Islamists.

In the same vein, Tamarod, the group that spearheaded the June 30 protests against Morsi and supports the new government, called the vandalism "regrettable."

The group also warned against protests Tuesday, saying the Brotherhood will try to infiltrate them and "drag the revolution into violence."

One of the military supporters in Tahrir, Zinat Fouad, said she was driven out of the square when activists threw stones. She said she had wanted to commemorate martyrs and show support for el-Sissi.

"Those who died are also our children," the 59-year-old employee of the tax agency said, wearing a military cap over her headscarf and an el-Sissi pins on her jacket.

But, she insisted, police were never to blame for protester deaths.

"They were killed by the Brotherhood, who wanted to divide Egyptians."